Razor wire tops one of the fences at the Lincoln Hills School for Boys and Copper Lake School for girls complex in rural Irma, Wis. Federal criminal and civil rights investigations probing allegations of abuse of juvenile offenders are underway at the facilities.(Photo: Dan Young / USA TODAY NETWORK-Wisconsin)Buy Photo

Nineteen months after agents and lawyers raided Wisconsin’s youth prison over allegations of inmate abuse and other crimes, the number of people housed there remains far below pre-raid levels.

State officials have touted numerous upgrades since the Dec. 5, 2015, raid. But the sustained population drop signals some local authorities remain leery of the prison as federal investigations continue.

A day before the raid, 264 youths were housed at the Lincoln Hills School for Boys and the Copper Lake School for Girls, according to state tallies. The facilities share a remote campus about 30 miles north of Wausau.

The population slid until August last year, reaching a low of 155 inmates, and then rebounded to about 180 inmates — still about 30% below pre-raid levels.

Milwaukee, Racine and Brown counties primarily caused the drop. The three counties sent about 100 youth to the prison last year, 57 fewer than the previous year. All other counties combined sent 66 youth inmates last year, 28 fewer than in 2015.

The drop spurred lawmakers this year to consider hiking how much county taxpayers must give the state for housing youth inmates. Counties currently pay about $300 daily per inmate. The rate would rise by about $100 under a state budget proposal.

Milwaukee and Racine county officials have been critical of the youth prison's conditions in recent years. A month after the raid, Milwaukee County Chief Judge Maxine White called the treatment of youth "inhumane" and urged authorities to provide sentencing alternatives. White declined to comment for this story.

Racine County admitted no youth to the prison last year after sending 10 or more in each of the previous three years. State corrections tallies show at least one youth has been sent to the prison through May of this year, ending the year-long streak.

Judge Wynne Laufenberg, who presides over Racine County's juvenile cases, said she has closely followed news reports about the prison and reviewed pleadings from an ongoing American Civil Liberties Union of Wisconsin lawsuit. The ACLU argues inmates at the prison are too often placed in solitary confinement and restraints, and pepper sprayed.

"It does appear from these reports and pleadings that the current scrutiny on practices within these institutions is warranted," Wynne, who was appointed to the bench in December by Gov. Scott Walker, wrote in an email.

Brown County criminal justice leaders haven’t criticized Wisconsin's youth prison since the raid but the county has also seen a drop in admissions. From 2012 to 2015, the county sent an average of about 11 teens annually to the prison. Last year, they sent three.

Brown County Judge William Atkinson, who presided over juvenile cases before another judge rotated into the position this year, attributed the drop to a local detention program backed by prosecutors and child welfare workers. The county expanded the program in 2015, reducing state prison admissions.

Brown County's juvenile prosecutor and two child welfare supervisors involved in the program said it provides greater local oversight of youth treatment, and allows parents to more easily visit their children and participate in counseling services. They believe it provides most youths with better treatment outcomes than a state prison.

"The parents are involved in this process with their son or daughter, which is very different than any other long-term juvenile correction facility in the state of Wisconsin," said Dannel Skalecki, who oversees youth justice services for the county. "Brown County started looking at this a long time before those issues (at Lincoln Hills and Copper Lake) came to light. Keeping kids local is best practice in juvenile justice."

Skalecki said just two Brown County teens are currently housed at the state prison in Irma, about a two-hour drive from Green Bay. From Milwaukee and Racine, it takes about three to four hours.

Two federal investigations of the prison remain ongoing. The FBI is reviewing allegations of child neglect, abuse of prisoners and other crimes while the U.S. Department of Justice is examining whether civil rights violations occurred. No corrections workers have been charged, although many have been fired or resigned amid scrutiny.

Since the December 2015 raid, the state Department of Corrections has dramatically expanded staff training at Lincoln Hills and equipped workers with body cameras. Critics contend the steps haven't been enough and last month a federal judge ruled the constitutional rights of inmates are likely being violated because of the institution’s heavy reliance on solitary confinement and pepper spray.

Aside from prison population, other common markers of youth involvement in Wisconsin’s criminal justice system didn’t see big changes last year. The number of juvenile court cases opened and resolved was about the same in 2015 and 2016. Wisconsin police agencies also reported arresting a similar number of youth each year for violent crimes.

Patrick Marley of the Milwaukee Journal Sentinel contributed to this report.

Keegan Kyle is an investigative reporter for USA TODAY NETWORK-Wisconsin. He can be reached at kkyle@gannett.com. Follow him on Twitter @keegankyle.